ESP32 ADC - Read Analog Values with Arduino IDE
Hàm sử dụng trong lập trình chức năng đọc ADC:
analogRead(ADC_pin);
- Chức năng: đọc giá trị analog tại ADC_pin
- Giá trị trả về: 0 -> 2n-1 với n là độ phân giải của bộ ADC ví dụ ADC 10 bit thì trả về giá trị 0 -> 210-1
Theo hình GPIO 15 dùng để đọc ADC vào từ biến trở.
CHƯƠNG TRÌNH ESP32_ARDUINO IDE.
// Mặc định 12 bit
// Potentiometer is connected to GPIO 34 (Analog ADC1_CH6)
const int GPIO_ADC= 34; // Chân 34 dùng để đọc ADC, gán chân 32 = GPIO_ADC.
// variable for storing the potentiometer value
int GIA_TRI_ADC_DOC_DUOC= 0;
void setup() {
Serial.begin(115200); // Tốc độ truyền lên, trên arduino IDE phải trùng.
delay(1000);
}
void loop() {
// Reading potentiometer value
GIA_TRI_ADC_DOC_DUOC= analogRead(GPIO_ADC);
Serial.println(GIA_TRI_ADC_DOC_DUOC);
delay(500);
}
FUNCTION ADC - CÁC BẠN CHÚ Ý NÊN ĐỌC :
- analogReadResolution(resolution): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
- analogSetWidth(width): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
- analogSetCycles(cycles): set the number of cycles per sample. Default is 8. Range: 1 to 255.
- analogSetSamples(samples): set the number of samples in the range. Default is 1 sample. It has an effect of increasing sensitivity.
- analogSetClockDiv(attenuation): set the divider for the ADC clock. Default is 1. Range: 1 to 255.
- analogSetAttenuation(attenuation): sets the input attenuation for all ADC pins. Default is ADC_11db. Accepted values:
- ADC_0db: sets no attenuation. ADC can measure up to approximately 800 mV (1V input = ADC reading of 1088).
- ADC_2_5db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1100 mV. (1V input = ADC reading of 3722).
- ADC_6db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1350 mV. (1V input = ADC reading of 3033).
- ADC_11db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 2600 mV. (1V input = ADC reading of 1575).
- analogSetPinAttenuation(pin, attenuation): sets the input attenuation for the specified pin. The default is ADC_11db. Attenuation values are the same from previous function.
- adcAttachPin(pin): Attach a pin to ADC (also clears any other analog mode that could be on). Returns TRUE or FALSE result.
- adcStart(pin), adcBusy(pin) and resultadcEnd(pin): starts an ADC convertion on attached pin’s bus. Check if conversion on the pin’s ADC bus is currently running (returns TRUE or FALSE). Get the result of the conversion: returns 16-bit integer.